The present invention relates to a phased array antenna and, more particularly, to methods for constructing and apparatus comprising the backplate of phased arrays that incorporate active electronic modules.
Present trends are to provide advances in phased array antennas for the EHF or millimeter wave frequency band. This band is roughly from 30-300 GHz, which corresponds to a wavelength of 1 cm-1 mm. The goal is to provide high power, light-weight and low cost antennas for the EHF band. Antenna arrays at the EHF band incorporate heat producing devices in the backplate thereof. These heat producing devices may include GaAs FET diodes, hybrid circuits, MMIC chips, VHSIC gate arrays, monolithic subarrays or other types of semiconductor devices or modules. Heat is also produced by RF transmission and distribution devices such as feed networks, planar waveguide power dividers, and the like. Furthermore, heat is also produced by the DC power distribution and buffering, as well as by control logic signal distribution and processing.
The complete antenna array with its backplate comprises a miniaturized structure having multiple layers. The purpose of the array backplate is to provide EHF signal distribution, DC power distribution, logic signal distribution, thermal management, and structural rigidity for subarray modules to be mounted thereon. It is desired that the EHF signal distribution be efficient (low signal loss), simple and highly reliable. It is also desired that the backplate be thin and light in weight. In particular, a thickness of 0.5 inch facilitates low profile mounting of the antenna array on aircraft.
It is an objective of the present invention to reduce or eliminate large number of thermal contact interfaces usually found in the cooling systems of conventional array backplates. It is also an objective to provide an array backplate that eliminates or reduces the high parts count typically found in conventional array backplates. Another objective is the provision of an array backplate that does not require a labor-intensive manufacturing process.